Orbit.java

  1. /* Copyright 2002-2019 CS Systèmes d'Information
  2.  * Licensed to CS Systèmes d'Information (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.orekit.orbits;

  19. import java.io.Serializable;

  21. import org.hipparchus.geometry.euclidean.threed.Vector3D;
  22. import org.hipparchus.linear.DecompositionSolver;
  23. import org.hipparchus.linear.MatrixUtils;
  24. import org.hipparchus.linear.QRDecomposition;
  25. import org.hipparchus.linear.RealMatrix;
  26. import org.hipparchus.util.FastMath;
  27. import org.hipparchus.util.MathArrays;
  28. import org.orekit.errors.OrekitIllegalArgumentException;
  29. import org.orekit.errors.OrekitInternalError;
  30. import org.orekit.errors.OrekitMessages;
  31. import org.orekit.frames.Frame;
  32. import org.orekit.frames.Transform;
  33. import org.orekit.time.AbsoluteDate;
  34. import org.orekit.time.TimeInterpolable;
  35. import org.orekit.time.TimeShiftable;
  36. import org.orekit.time.TimeStamped;
  37. import org.orekit.utils.PVCoordinates;
  38. import org.orekit.utils.PVCoordinatesProvider;
  39. import org.orekit.utils.TimeStampedPVCoordinates;

  41. /**
  42.  * This class handles orbital parameters.

  44.  * <p>
  45.  * For user convenience, both the Cartesian and the equinoctial elements
  46.  * are provided by this class, regardless of the canonical representation
  47.  * implemented in the derived class (which may be classical Keplerian
  48.  * elements for example).
  49.  * </p>
  50.  * <p>
  51.  * The parameters are defined in a frame specified by the user. It is important
  52.  * to make sure this frame is consistent: it probably is inertial and centered
  53.  * on the central body. This information is used for example by some
  54.  * force models.
  55.  * </p>
  56.  * <p>
  57.  * Instance of this class are guaranteed to be immutable.
  58.  * </p>
  59.  * @author Luc Maisonobe
  60.  * @author Guylaine Prat
  61.  * @author Fabien Maussion
  62.  * @author V&eacute;ronique Pommier-Maurussane
  63.  */
  64. public abstract class Orbit
  65.     implements TimeStamped, TimeShiftable<Orbit>, TimeInterpolable<Orbit>,
  66.                Serializable, PVCoordinatesProvider {

  68.     /** Serializable UID. */
  69.     private static final long serialVersionUID = 438733454597999578L;

  71.     /** Frame in which are defined the orbital parameters. */
  72.     private final Frame frame;

  74.     /** Date of the orbital parameters. */
  75.     private final AbsoluteDate date;

  77.     /** Value of mu used to compute position and velocity (m³/s²). */
  78.     private final double mu;

  80.     /** Computed PVCoordinates. */
  81.     private transient TimeStampedPVCoordinates pvCoordinates;

  83.     /** Jacobian of the orbital parameters with mean angle with respect to the Cartesian coordinates. */
  84.     private transient double[][] jacobianMeanWrtCartesian;

  86.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with mean angle. */
  87.     private transient double[][] jacobianWrtParametersMean;

  89.     /** Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian coordinates. */
  90.     private transient double[][] jacobianEccentricWrtCartesian;

  92.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with eccentric angle. */
  93.     private transient double[][] jacobianWrtParametersEccentric;

  95.     /** Jacobian of the orbital parameters with true angle with respect to the Cartesian coordinates. */
  96.     private transient double[][] jacobianTrueWrtCartesian;

  98.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with true angle. */
  99.     private transient double[][] jacobianWrtParametersTrue;

  101.     /** Default constructor.
  102.      * Build a new instance with arbitrary default elements.
  103.      * @param frame the frame in which the parameters are defined
  104.      * (<em>must</em> be a {@link Frame#isPseudoInertial pseudo-inertial frame})
  105.      * @param date date of the orbital parameters
  106.      * @param mu central attraction coefficient (m^3/s^2)
  107.      * @exception IllegalArgumentException if frame is not a {@link
  108.      * Frame#isPseudoInertial pseudo-inertial frame}
  109.      */
  110.     protected Orbit(final Frame frame, final AbsoluteDate date, final double mu)
  111.         throws IllegalArgumentException {
  112.         ensurePseudoInertialFrame(frame);
  113.         this.date                      = date;
  114.         this.mu                        = mu;
  115.         this.pvCoordinates             = null;
  116.         this.frame                     = frame;
  117.         jacobianMeanWrtCartesian       = null;
  118.         jacobianWrtParametersMean      = null;
  119.         jacobianEccentricWrtCartesian  = null;
  120.         jacobianWrtParametersEccentric = null;
  121.         jacobianTrueWrtCartesian       = null;
  122.         jacobianWrtParametersTrue      = null;
  123.     }

  125.     /** Set the orbit from Cartesian parameters.
  126.      *
  127.      * <p> The acceleration provided in {@code pvCoordinates} is accessible using
  128.      * {@link #getPVCoordinates()} and {@link #getPVCoordinates(Frame)}. All other methods
  129.      * use {@code mu} and the position to compute the acceleration, including
  130.      * {@link #shiftedBy(double)} and {@link #getPVCoordinates(AbsoluteDate, Frame)}.
  131.      *
  132.      * @param pvCoordinates the position and velocity in the inertial frame
  133.      * @param frame the frame in which the {@link TimeStampedPVCoordinates} are defined
  134.      * (<em>must</em> be a {@link Frame#isPseudoInertial pseudo-inertial frame})
  135.      * @param mu central attraction coefficient (m^3/s^2)
  136.      * @exception IllegalArgumentException if frame is not a {@link
  137.      * Frame#isPseudoInertial pseudo-inertial frame}
  138.      */
  139.     protected Orbit(final TimeStampedPVCoordinates pvCoordinates, final Frame frame, final double mu)
  140.         throws IllegalArgumentException {
  141.         ensurePseudoInertialFrame(frame);
  142.         this.date = pvCoordinates.getDate();
  143.         this.mu = mu;
  144.         if (pvCoordinates.getAcceleration().getNormSq() == 0) {
  145.             // the acceleration was not provided,
  146.             // compute it from Newtonian attraction
  147.             final double r2 = pvCoordinates.getPosition().getNormSq();
  148.             final double r3 = r2 * FastMath.sqrt(r2);
  149.             this.pvCoordinates = new TimeStampedPVCoordinates(pvCoordinates.getDate(),
  150.                                                               pvCoordinates.getPosition(),
  151.                                                               pvCoordinates.getVelocity(),
  152.                                                               new Vector3D(-mu / r3, pvCoordinates.getPosition()));
  153.         } else {
  154.             this.pvCoordinates = pvCoordinates;
  155.         }
  156.         this.frame = frame;
  157.     }

  159.     /** Check if Cartesian coordinates include non-Keplerian acceleration.
  160.      * @param pva Cartesian coordinates
  161.      * @param mu central attraction coefficient
  162.      * @return true if Cartesian coordinates include non-Keplerian acceleration
  163.      */
  164.     protected static boolean hasNonKeplerianAcceleration(final PVCoordinates pva, final double mu) {

  166.         final Vector3D a = pva.getAcceleration();
  167.         if (a == null) {
  168.             return false;
  169.         }

  171.         final Vector3D p = pva.getPosition();
  172.         final double r2 = p.getNormSq();
  173.         final double r  = FastMath.sqrt(r2);
  174.         final Vector3D keplerianAcceleration = new Vector3D(-mu / (r * r2), p);
  175.         if (a.getNorm() > 1.0e-9 * keplerianAcceleration.getNorm()) {
  176.             // we have a relevant acceleration, we can compute derivatives
  177.             return true;
  178.         } else {
  179.             // the provided acceleration is either too small to be reliable (probably even 0), or NaN
  180.             return false;
  181.         }

  183.     }

  185.     /** Get the orbit type.
  186.      * @return orbit type
  187.      */
  188.     public abstract OrbitType getType();

  190.     /** Ensure the defining frame is a pseudo-inertial frame.
  191.      * @param frame frame to check
  192.      * @exception IllegalArgumentException if frame is not a {@link
  193.      * Frame#isPseudoInertial pseudo-inertial frame}
  194.      */
  195.     private static void ensurePseudoInertialFrame(final Frame frame)
  196.         throws IllegalArgumentException {
  197.         if (!frame.isPseudoInertial()) {
  198.             throw new OrekitIllegalArgumentException(OrekitMessages.NON_PSEUDO_INERTIAL_FRAME,
  199.                                                      frame.getName());
  200.         }
  201.     }

  203.     /** Get the frame in which the orbital parameters are defined.
  204.      * @return frame in which the orbital parameters are defined
  205.      */
  206.     public Frame getFrame() {
  207.         return frame;
  208.     }

  210.     /** Get the semi-major axis.
  211.      * <p>Note that the semi-major axis is considered negative for hyperbolic orbits.</p>
  212.      * @return semi-major axis (m)
  213.      */
  214.     public abstract double getA();

  216.     /** Get the semi-major axis derivative.
  217.      * <p>Note that the semi-major axis is considered negative for hyperbolic orbits.</p>
  218.      * <p>
  219.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  220.      * </p>
  221.      * @return semi-major axis  derivative (m/s)
  222.      * @see #hasDerivatives()
  223.      * @since 9.0
  224.      */
  225.     public abstract double getADot();

  227.     /** Get the first component of the equinoctial eccentricity vector derivative.
  228.      * @return first component of the equinoctial eccentricity vector derivative
  229.      */
  230.     public abstract double getEquinoctialEx();

  232.     /** Get the first component of the equinoctial eccentricity vector.
  233.      * <p>
  234.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  235.      * </p>
  236.      * @return first component of the equinoctial eccentricity vector
  237.      * @see #hasDerivatives()
  238.      * @since 9.0
  239.      */
  240.     public abstract double getEquinoctialExDot();

  242.     /** Get the second component of the equinoctial eccentricity vector derivative.
  243.      * @return second component of the equinoctial eccentricity vector derivative
  244.      */
  245.     public abstract double getEquinoctialEy();

  247.     /** Get the second component of the equinoctial eccentricity vector.
  248.      * <p>
  249.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  250.      * </p>
  251.      * @return second component of the equinoctial eccentricity vector
  252.      * @see #hasDerivatives()
  253.      * @since 9.0
  254.      */
  255.     public abstract double getEquinoctialEyDot();

  257.     /** Get the first component of the inclination vector.
  258.      * @return first component of the inclination vector
  259.      */
  260.     public abstract double getHx();

  262.     /** Get the first component of the inclination vector derivative.
  263.      * <p>
  264.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  265.      * </p>
  266.      * @return first component of the inclination vector derivative
  267.      * @see #hasDerivatives()
  268.      * @since 9.0
  269.      */
  270.     public abstract double getHxDot();

  272.     /** Get the second component of the inclination vector.
  273.      * @return second component of the inclination vector
  274.      */
  275.     public abstract double getHy();

  277.     /** Get the second component of the inclination vector derivative.
  278.      * <p>
  279.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  280.      * </p>
  281.      * @return second component of the inclination vector derivative
  282.      * @see #hasDerivatives()
  283.      * @since 9.0
  284.      */
  285.     public abstract double getHyDot();

  287.     /** Get the eccentric longitude argument.
  288.      * @return E + ω + Ω eccentric longitude argument (rad)
  289.      */
  290.     public abstract double getLE();

  292.     /** Get the eccentric longitude argument derivative.
  293.      * <p>
  294.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  295.      * </p>
  296.      * @return d(E + ω + Ω)/dt eccentric longitude argument derivative (rad/s)
  297.      * @see #hasDerivatives()
  298.      * @since 9.0
  299.      */
  300.     public abstract double getLEDot();

  302.     /** Get the true longitude argument.
  303.      * @return v + ω + Ω true longitude argument (rad)
  304.      */
  305.     public abstract double getLv();

  307.     /** Get the true longitude argument derivative.
  308.      * <p>
  309.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  310.      * </p>
  311.      * @return d(v + ω + Ω)/dt true longitude argument derivative (rad/s)
  312.      * @see #hasDerivatives()
  313.      * @since 9.0
  314.      */
  315.     public abstract double getLvDot();

  317.     /** Get the mean longitude argument.
  318.      * @return M + ω + Ω mean longitude argument (rad)
  319.      */
  320.     public abstract double getLM();

  322.     /** Get the mean longitude argument derivative.
  323.      * <p>
  324.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  325.      * </p>
  326.      * @return d(M + ω + Ω)/dt mean longitude argument derivative (rad/s)
  327.      * @see #hasDerivatives()
  328.      * @since 9.0
  329.      */
  330.     public abstract double getLMDot();

  332.     // Additional orbital elements

  334.     /** Get the eccentricity.
  335.      * @return eccentricity
  336.      */
  337.     public abstract double getE();

  339.     /** Get the eccentricity derivative.
  340.      * <p>
  341.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  342.      * </p>
  343.      * @return eccentricity derivative
  344.      * @see #hasDerivatives()
  345.      * @since 9.0
  346.      */
  347.     public abstract double getEDot();

  349.     /** Get the inclination.
  350.      * @return inclination (rad)
  351.      */
  352.     public abstract double getI();

  354.     /** Get the inclination derivative.
  355.      * <p>
  356.      * If the orbit was created without derivatives, the value returned is {@link Double#NaN}.
  357.      * </p>
  358.      * @return inclination derivative (rad/s)
  359.      * @see #hasDerivatives()
  360.      * @since 9.0
  361.      */
  362.     public abstract double getIDot();

  364.     /** Check if orbit includes derivatives.
  365.      * @return true if orbit includes derivatives
  366.      * @see #getADot()
  367.      * @see #getEquinoctialExDot()
  368.      * @see #getEquinoctialEyDot()
  369.      * @see #getHxDot()
  370.      * @see #getHyDot()
  371.      * @see #getLEDot()
  372.      * @see #getLvDot()
  373.      * @see #getLMDot()
  374.      * @see #getEDot()
  375.      * @see #getIDot()
  376.      * @since 9.0
  377.      */
  378.     public boolean hasDerivatives() {
  379.         return !Double.isNaN(getADot());
  380.     }

  382.     /** Get the central acceleration constant.
  383.      * @return central acceleration constant
  384.      */
  385.     public double getMu() {
  386.         return mu;
  387.     }

  389.     /** Get the Keplerian period.
  390.      * <p>The Keplerian period is computed directly from semi major axis
  391.      * and central acceleration constant.</p>
  392.      * @return Keplerian period in seconds, or positive infinity for hyperbolic orbits
  393.      */
  394.     public double getKeplerianPeriod() {
  395.         final double a = getA();
  396.         return (a < 0) ? Double.POSITIVE_INFINITY : 2.0 * FastMath.PI * a * FastMath.sqrt(a / mu);
  397.     }

  399.     /** Get the Keplerian mean motion.
  400.      * <p>The Keplerian mean motion is computed directly from semi major axis
  401.      * and central acceleration constant.</p>
  402.      * @return Keplerian mean motion in radians per second
  403.      */
  404.     public double getKeplerianMeanMotion() {
  405.         final double absA = FastMath.abs(getA());
  406.         return FastMath.sqrt(mu / absA) / absA;
  407.     }

  409.     /** Get the date of orbital parameters.
  410.      * @return date of the orbital parameters
  411.      */
  412.     public AbsoluteDate getDate() {
  413.         return date;
  414.     }

  416.     /** Get the {@link TimeStampedPVCoordinates} in a specified frame.
  417.      * @param outputFrame frame in which the position/velocity coordinates shall be computed
  418.      * @return pvCoordinates in the specified output frame
  419.           * @see #getPVCoordinates()
  420.      */
  421.     public TimeStampedPVCoordinates getPVCoordinates(final Frame outputFrame) {
  422.         if (pvCoordinates == null) {
  423.             pvCoordinates = initPVCoordinates();
  424.         }

  426.         // If output frame requested is the same as definition frame,
  427.         // PV coordinates are returned directly
  428.         if (outputFrame == frame) {
  429.             return pvCoordinates;
  430.         }

  432.         // Else, PV coordinates are transformed to output frame
  433.         final Transform t = frame.getTransformTo(outputFrame, date);
  434.         return t.transformPVCoordinates(pvCoordinates);
  435.     }

  437.     /** {@inheritDoc} */
  438.     public TimeStampedPVCoordinates getPVCoordinates(final AbsoluteDate otherDate, final Frame otherFrame) {
  439.         return shiftedBy(otherDate.durationFrom(getDate())).getPVCoordinates(otherFrame);
  440.     }


  443.     /** Get the {@link TimeStampedPVCoordinates} in definition frame.
  444.      * @return pvCoordinates in the definition frame
  445.      * @see #getPVCoordinates(Frame)
  446.      */
  447.     public TimeStampedPVCoordinates getPVCoordinates() {
  448.         if (pvCoordinates == null) {
  449.             pvCoordinates = initPVCoordinates();
  450.         }
  451.         return pvCoordinates;
  452.     }

  454.     /** Compute the position/velocity coordinates from the canonical parameters.
  455.      * @return computed position/velocity coordinates
  456.      */
  457.     protected abstract TimeStampedPVCoordinates initPVCoordinates();

  459.     /** Get a time-shifted orbit.
  460.      * <p>
  461.      * The orbit can be slightly shifted to close dates. The shifting model is a
  462.      * Keplerian one if no derivatives are available in the orbit, or Keplerian
  463.      * plus quadratic effect of the non-Keplerian acceleration if derivatives are
  464.      * available. Shifting is <em>not</em> intended as a replacement for proper
  465.      * orbit propagation but should be sufficient for small time shifts or coarse
  466.      * accuracy.
  467.      * </p>
  468.      * @param dt time shift in seconds
  469.      * @return a new orbit, shifted with respect to the instance (which is immutable)
  470.      */
  471.     public abstract Orbit shiftedBy(double dt);

  473.     /** Compute the Jacobian of the orbital parameters with respect to the Cartesian parameters.
  474.      * <p>
  475.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  476.      * respect to Cartesian coordinate j. This means each row corresponds to one orbital parameter
  477.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  478.      * </p>
  479.      * @param type type of the position angle to use
  480.      * @param jacobian placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix
  481.      * is larger than 6x6, only the 6x6 upper left corner will be modified
  482.      */
  483.     public void getJacobianWrtCartesian(final PositionAngle type, final double[][] jacobian) {

  485.         final double[][] cachedJacobian;
  486.         synchronized (this) {
  487.             switch (type) {
  488.                 case MEAN :
  489.                     if (jacobianMeanWrtCartesian == null) {
  490.                         // first call, we need to compute the Jacobian and cache it
  491.                         jacobianMeanWrtCartesian = computeJacobianMeanWrtCartesian();
  492.                     }
  493.                     cachedJacobian = jacobianMeanWrtCartesian;
  494.                     break;
  495.                 case ECCENTRIC :
  496.                     if (jacobianEccentricWrtCartesian == null) {
  497.                         // first call, we need to compute the Jacobian and cache it
  498.                         jacobianEccentricWrtCartesian = computeJacobianEccentricWrtCartesian();
  499.                     }
  500.                     cachedJacobian = jacobianEccentricWrtCartesian;
  501.                     break;
  502.                 case TRUE :
  503.                     if (jacobianTrueWrtCartesian == null) {
  504.                         // first call, we need to compute the Jacobian and cache it
  505.                         jacobianTrueWrtCartesian = computeJacobianTrueWrtCartesian();
  506.                     }
  507.                     cachedJacobian = jacobianTrueWrtCartesian;
  508.                     break;
  509.                 default :
  510.                     throw new OrekitInternalError(null);
  511.             }
  512.         }

  514.         // fill the user provided array
  515.         for (int i = 0; i < cachedJacobian.length; ++i) {
  516.             System.arraycopy(cachedJacobian[i], 0, jacobian[i], 0, cachedJacobian[i].length);
  517.         }

  519.     }

  521.     /** Compute the Jacobian of the Cartesian parameters with respect to the orbital parameters.
  522.      * <p>
  523.      * Element {@code jacobian[i][j]} is the derivative of Cartesian coordinate i of the orbit with
  524.      * respect to orbital parameter j. This means each row corresponds to one Cartesian coordinate
  525.      * x, y, z, xdot, ydot, zdot whereas columns 0 to 5 correspond to the orbital parameters.
  526.      * </p>
  527.      * @param type type of the position angle to use
  528.      * @param jacobian placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix
  529.      * is larger than 6x6, only the 6x6 upper left corner will be modified
  530.      */
  531.     public void getJacobianWrtParameters(final PositionAngle type, final double[][] jacobian) {

  533.         final double[][] cachedJacobian;
  534.         synchronized (this) {
  535.             switch (type) {
  536.                 case MEAN :
  537.                     if (jacobianWrtParametersMean == null) {
  538.                         // first call, we need to compute the Jacobian and cache it
  539.                         jacobianWrtParametersMean = createInverseJacobian(type);
  540.                     }
  541.                     cachedJacobian = jacobianWrtParametersMean;
  542.                     break;
  543.                 case ECCENTRIC :
  544.                     if (jacobianWrtParametersEccentric == null) {
  545.                         // first call, we need to compute the Jacobian and cache it
  546.                         jacobianWrtParametersEccentric = createInverseJacobian(type);
  547.                     }
  548.                     cachedJacobian = jacobianWrtParametersEccentric;
  549.                     break;
  550.                 case TRUE :
  551.                     if (jacobianWrtParametersTrue == null) {
  552.                         // first call, we need to compute the Jacobian and cache it
  553.                         jacobianWrtParametersTrue = createInverseJacobian(type);
  554.                     }
  555.                     cachedJacobian = jacobianWrtParametersTrue;
  556.                     break;
  557.                 default :
  558.                     throw new OrekitInternalError(null);
  559.             }
  560.         }

  562.         // fill the user-provided array
  563.         for (int i = 0; i < cachedJacobian.length; ++i) {
  564.             System.arraycopy(cachedJacobian[i], 0, jacobian[i], 0, cachedJacobian[i].length);
  565.         }

  567.     }

  569.     /** Create an inverse Jacobian.
  570.      * @param type type of the position angle to use
  571.      * @return inverse Jacobian
  572.      */
  573.     private double[][] createInverseJacobian(final PositionAngle type) {

  575.         // get the direct Jacobian
  576.         final double[][] directJacobian = new double[6][6];
  577.         getJacobianWrtCartesian(type, directJacobian);

  579.         // invert the direct Jacobian
  580.         final RealMatrix matrix = MatrixUtils.createRealMatrix(directJacobian);
  581.         final DecompositionSolver solver = new QRDecomposition(matrix).getSolver();
  582.         return solver.getInverse().getData();

  584.     }

  586.     /** Compute the Jacobian of the orbital parameters with mean angle with respect to the Cartesian parameters.
  587.      * <p>
  588.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  589.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  590.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  591.      * </p>
  592.      * @return 6x6 Jacobian matrix
  593.      * @see #computeJacobianEccentricWrtCartesian()
  594.      * @see #computeJacobianTrueWrtCartesian()
  595.      */
  596.     protected abstract double[][] computeJacobianMeanWrtCartesian();

  598.     /** Compute the Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian parameters.
  599.      * <p>
  600.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  601.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  602.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  603.      * </p>
  604.      * @return 6x6 Jacobian matrix
  605.      * @see #computeJacobianMeanWrtCartesian()
  606.      * @see #computeJacobianTrueWrtCartesian()
  607.      */
  608.     protected abstract double[][] computeJacobianEccentricWrtCartesian();

  610.     /** Compute the Jacobian of the orbital parameters with true angle with respect to the Cartesian parameters.
  611.      * <p>
  612.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  613.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  614.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  615.      * </p>
  616.      * @return 6x6 Jacobian matrix
  617.      * @see #computeJacobianMeanWrtCartesian()
  618.      * @see #computeJacobianEccentricWrtCartesian()
  619.      */
  620.     protected abstract double[][] computeJacobianTrueWrtCartesian();

  622.     /** Add the contribution of the Keplerian motion to parameters derivatives
  623.      * <p>
  624.      * This method is used by integration-based propagators to evaluate the part of Keplerian
  625.      * motion to evolution of the orbital state.
  626.      * </p>
  627.      * @param type type of the position angle in the state
  628.      * @param gm attraction coefficient to use
  629.      * @param pDot array containing orbital state derivatives to update (the Keplerian
  630.      * part must be <em>added</em> to the array components, as the array may already
  631.      * contain some non-zero elements corresponding to non-Keplerian parts)
  632.      */
  633.     public abstract void addKeplerContribution(PositionAngle type, double gm, double[] pDot);

  635.         /** Fill a Jacobian half row with a single vector.
  636.      * @param a coefficient of the vector
  637.      * @param v vector
  638.      * @param row Jacobian matrix row
  639.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  640.      */
  641.     protected static void fillHalfRow(final double a, final Vector3D v, final double[] row, final int j) {
  642.         row[j]     = a * v.getX();
  643.         row[j + 1] = a * v.getY();
  644.         row[j + 2] = a * v.getZ();
  645.     }

  647.     /** Fill a Jacobian half row with a linear combination of vectors.
  648.      * @param a1 coefficient of the first vector
  649.      * @param v1 first vector
  650.      * @param a2 coefficient of the second vector
  651.      * @param v2 second vector
  652.      * @param row Jacobian matrix row
  653.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  654.      */
  655.     protected static void fillHalfRow(final double a1, final Vector3D v1, final double a2, final Vector3D v2,
  656.                                       final double[] row, final int j) {
  657.         row[j]     = MathArrays.linearCombination(a1, v1.getX(), a2, v2.getX());
  658.         row[j + 1] = MathArrays.linearCombination(a1, v1.getY(), a2, v2.getY());
  659.         row[j + 2] = MathArrays.linearCombination(a1, v1.getZ(), a2, v2.getZ());
  660.     }

  662.     /** Fill a Jacobian half row with a linear combination of vectors.
  663.      * @param a1 coefficient of the first vector
  664.      * @param v1 first vector
  665.      * @param a2 coefficient of the second vector
  666.      * @param v2 second vector
  667.      * @param a3 coefficient of the third vector
  668.      * @param v3 third vector
  669.      * @param row Jacobian matrix row
  670.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  671.      */
  672.     protected static void fillHalfRow(final double a1, final Vector3D v1, final double a2, final Vector3D v2,
  673.                                       final double a3, final Vector3D v3,
  674.                                       final double[] row, final int j) {
  675.         row[j]     = MathArrays.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX());
  676.         row[j + 1] = MathArrays.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY());
  677.         row[j + 2] = MathArrays.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ());
  678.     }

  680.     /** Fill a Jacobian half row with a linear combination of vectors.
  681.      * @param a1 coefficient of the first vector
  682.      * @param v1 first vector
  683.      * @param a2 coefficient of the second vector
  684.      * @param v2 second vector
  685.      * @param a3 coefficient of the third vector
  686.      * @param v3 third vector
  687.      * @param a4 coefficient of the fourth vector
  688.      * @param v4 fourth vector
  689.      * @param row Jacobian matrix row
  690.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  691.      */
  692.     protected static void fillHalfRow(final double a1, final Vector3D v1, final double a2, final Vector3D v2,
  693.                                       final double a3, final Vector3D v3, final double a4, final Vector3D v4,
  694.                                       final double[] row, final int j) {
  695.         row[j]     = MathArrays.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX(), a4, v4.getX());
  696.         row[j + 1] = MathArrays.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY(), a4, v4.getY());
  697.         row[j + 2] = MathArrays.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ(), a4, v4.getZ());
  698.     }

  700.     /** Fill a Jacobian half row with a linear combination of vectors.
  701.      * @param a1 coefficient of the first vector
  702.      * @param v1 first vector
  703.      * @param a2 coefficient of the second vector
  704.      * @param v2 second vector
  705.      * @param a3 coefficient of the third vector
  706.      * @param v3 third vector
  707.      * @param a4 coefficient of the fourth vector
  708.      * @param v4 fourth vector
  709.      * @param a5 coefficient of the fifth vector
  710.      * @param v5 fifth vector
  711.      * @param row Jacobian matrix row
  712.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  713.      */
  714.     protected static void fillHalfRow(final double a1, final Vector3D v1, final double a2, final Vector3D v2,
  715.                                       final double a3, final Vector3D v3, final double a4, final Vector3D v4,
  716.                                       final double a5, final Vector3D v5,
  717.                                       final double[] row, final int j) {
  718.         final double[] a = new double[] {
  719.             a1, a2, a3, a4, a5
  720.         };
  721.         row[j]     = MathArrays.linearCombination(a, new double[] {
  722.             v1.getX(), v2.getX(), v3.getX(), v4.getX(), v5.getX()
  723.         });
  724.         row[j + 1] = MathArrays.linearCombination(a, new double[] {
  725.             v1.getY(), v2.getY(), v3.getY(), v4.getY(), v5.getY()
  726.         });
  727.         row[j + 2] = MathArrays.linearCombination(a, new double[] {
  728.             v1.getZ(), v2.getZ(), v3.getZ(), v4.getZ(), v5.getZ()
  729.         });
  730.     }

  732.     /** Fill a Jacobian half row with a linear combination of vectors.
  733.      * @param a1 coefficient of the first vector
  734.      * @param v1 first vector
  735.      * @param a2 coefficient of the second vector
  736.      * @param v2 second vector
  737.      * @param a3 coefficient of the third vector
  738.      * @param v3 third vector
  739.      * @param a4 coefficient of the fourth vector
  740.      * @param v4 fourth vector
  741.      * @param a5 coefficient of the fifth vector
  742.      * @param v5 fifth vector
  743.      * @param a6 coefficient of the sixth vector
  744.      * @param v6 sixth vector
  745.      * @param row Jacobian matrix row
  746.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  747.      */
  748.     protected static void fillHalfRow(final double a1, final Vector3D v1, final double a2, final Vector3D v2,
  749.                                       final double a3, final Vector3D v3, final double a4, final Vector3D v4,
  750.                                       final double a5, final Vector3D v5, final double a6, final Vector3D v6,
  751.                                       final double[] row, final int j) {
  752.         final double[] a = new double[] {
  753.             a1, a2, a3, a4, a5, a6
  754.         };
  755.         row[j]     = MathArrays.linearCombination(a, new double[] {
  756.             v1.getX(), v2.getX(), v3.getX(), v4.getX(), v5.getX(), v6.getX()
  757.         });
  758.         row[j + 1] = MathArrays.linearCombination(a, new double[] {
  759.             v1.getY(), v2.getY(), v3.getY(), v4.getY(), v5.getY(), v6.getY()
  760.         });
  761.         row[j + 2] = MathArrays.linearCombination(a, new double[] {
  762.             v1.getZ(), v2.getZ(), v3.getZ(), v4.getZ(), v5.getZ(), v6.getZ()
  763.         });
  764.     }

  766. }
Created with JaCoCo 0.8.2.201808211720